Electric perforating machine



H. c. STEFFENS ELECTRIC PERFORM-me MACHINE v med Feb. 9. 1924 //vvE TDR.

HENRYLIETEF ENs. I BY h ,ATTDRNEYS.

Patented Nov. 29, 1927.

PATENT OFFICE.

HENRY C. STEFFENS, OF SAN FRANCISCO, CALII'ORNIA.

ELECTRIC PERFORA'IING MACHINE.

Application filed February 9, 1924. Serial No. 691,868.

This invention relates to a perforating machine, and particularly to a machine .whereby paper stencils may be traced upon ing machines; to provide means for increasing or decreasing the intensity or current of the spark so as to produce perforations both fine, intermediate and coarse; to provide a pencil whereby tracing and perioration are simultaneously accomplished, and further, to provide means whereby the circuit through the pencil and the machine is automatically closed when the ncil is employed, and conversely opened w en the pencil is laid down.

One form which my invention may assume is exemplified in the following description and illustrated in the accompanying drawings, in whic h- 1g. 1 is a diagrammatic view showing the electric circuits employed in the perforating machine.

Fig. 2 is alongitudinal sectional view of the pencil.

Referring to the drawings in detail, and

. particularly to Fig. 1, A indicates, in general, a transformer, the primary winding 2 of which is connected with a suitable source of alternating current supply through wires 3 and 4. Interposed between the wire 4 and the primary winding of the transformer is an incandescent bulb 5 which is employed as a resistance, and connected therewith is a switch 6. The wire 4 is connected to the terminal 7 of the bulb and this terminal is in turn connected through .a wire 8 with one contact 9, of the switch. The other terminal of the bulb is connected through a wire 10 with the opposite terminal of the switch and the main'termin'al of the switch is connected through a wire 11 with one side of the primary winding. If the switch lever engages the contact 9, no resistance is imposed on the circuit as the current will pass through the wires 4, 8 and 11, but, if the switch is thrown into engagement with the opposite contact, the current will pass throu h the bulb, the

- wire 10 and the wire 11, t us imposing a predetermined amount of resistance. 1

The secondary Winding of the transformer indicated at 12 is connected at one end through a. re 13 with a switch 14. The other term nal of the secondary winding is connected through a wire 15 with a grounding-plate 16.- A condenser of suitable capacity indicated at 17 is connected between the wires 15 and 13 and a resistance-in the form of an incandescent bulb such as indicated at 18 is also imposed on the secondary clrcuit.

The apparatus here illustrated perforates paper and like materials by means of an electric spark action and a pencil generally indicated at B is employed in connection with the grounding plate 16 for this purpose. The pencil may be of any suitable shape, but it is in this instance cylindrical and elongated. It consists of a tube or rod of insulating material such as indicated at 19 through the center portion of which exof thepencil contains a bulb 21 which is partially filled with mercury as indicated at 22. The bulb is provided with two terminals, a central rod like terminal 23 extending downwardly into the bulb, and an end terminal such as indicated at 24. :The central rod terminal 23 is connected through a wire 25' with one end of the primary winding of nected through the wire 13 with one end of the secondary winding 12 of the transformer.

The bulb 21 containing the mercury and the two contacts 23 and 24 serve as an automatic switch. If the pencil. is grasped and held in an inclined or vertical position, the mercury runs downto the end of the bulb and as such closes a circuit between the terminals or contacts 23 and 24. This in turn closes the circuit through the primray winding of the transformer. This'circuit can be traced as follows:

The alternating current coming in on the wire 3 passes through the contact 24, the

then passes through the 'wire 25, the primary winding 2,' then" throng-Ill1 wire .11, switch 6, contact 9, wire.8, and ally passes out through the main feed wire 4; that is,

, tends a conductor or rod 20. The upper end mercury 22 and the second contact 23. It

so d

it takes this circuit if the switch lever in switch 6 is thrown into engagement with contact 9, but if a resistance is desired, the circuit passes through wire 11 and the opposite contact, then through wire 10 and the bulb and finally out through the wire 4, the circuit passing through wire 8 when no re sistance is desired and through wire 10 and the bulb when resistance is required.

The secondary circuit is established when the main terminal of the pencil indicated at 20 is brought into contact with the groundin plate 16. This circuit can be traced as fo lows:

The current from the secondary winding in the condenser passes out through wire 13 to the switch l l. If no resistance is required, the switch lever engages contact 27 and the current will thus pass through the wire 26, the rod terminal 20, plate 16, and it will then return on the wire 15 to the secondary winding and the condenser. If resistance is desired, the switch lever is thrown into engagement with the opposite contact of the switch 14:. The current will then pass through the wire 29, bulb 18 and wires 28 and 26.

In actual operation if it is desired'to make a perforated tracing of a stencil, figure, esign or otherwise, it is only necessary to place the original on top of the grounding plate 16. A. sheet of transparent paper is then placed on top of the object to be traced and the pencil terminal 20 is then traced over the lines appearing through the paper. If fine perforations are desired, both resistances, to-wit, bulbs 5 and 18, are employed. If an intermediate sized perforation is desired, one or the other of the bulbs may be cut out, and if a coarse perforation is required, both bulbs are cut out of the circuit so as to impose no resistance.

I Iwo or three sheets and often more may be perforated atone time by merely placing one on top of the other and, as this is the case, it can readily-be seen that means must be employed for varying the intensity of the current or the spark produced, this being accomplished as previously stated by employing one or more resistances as illustrated.

While the apparatus here shown is more or less specifically illustrated, I wish it understood that various changes in form and proportion may be resorted to .within the scope of the appended claims. I similarly wish it understood that the materials and finish of the several parts employed may be such as the experience and judgment of the manufacturer may dictate or various uses may demand.

While the apparatus here illustrated has been described as'a tracing and perforating device for making stencils or the like, I wish it understood that it may also be employed for the purpose of signin checks and for perforating the same. ere it is desired. to perforate a check it is possible to employ an electrode which is provided with a fiat straight edge. This edge when drawn over a check will perforate it in innumerable places, and if a duplicate check is disposed below the same, one will serve asa duplicate for purposes of comparison to prevent fraud,

etc.

Having thus described my invention, what I claim and desire to secure by Letters Patent is a 1. An electric perforating apparatus com prising a bed plate adapted to receive paper sheets to be traced and perforated, an electrodepencil for tracing and perforation, a transformer, the primary winding of said transformer adapted to be connected with a source of alternating current supply, a secondary winding in the transformer, one terminal of the secondary winding being counected with the bed plate and the other terminal of the secondary winding being connected to the electrode-pencil, a condenser connected between the terminals of the secondary winding, a resistance placed in the secondary circuit of the transformer, and a switch for throwing said resistance into or out of operation.

2. An electric perforating apparatus comprising a bed plate adapted to receive paper sheets to be traced and perforated, an electrode-pencil for tracing and perforation, a transformer, the primary winding of said transformer adapted to be connected. with a source of alternatin current supply, asecondary Winding in t e transformer, one terminal of the secondary windin being connected with the bed plate, and t e other terminal of the secondary winding bein connected to the electrode-pencil, a condenser connected between the terminals of the secondary windinggand a mercury switch in the electrode-pencil and interposed in the alternating current circuit of the primary winding, said switch automatically closin a circult through the primary windin w en the pencil assumes a vertical or a su stantially vertical position, and automaticall opening the circuit when the pencil is laid at.

3. In an apparatus of the character described, a transformer having a primary and a secondary winding, a bed plate, a pencilelectrode cooperating therewith, said pencil being connected both with the primary and the secondary winding of the transformer, and controlling the current flow through both.

HENRY C. STEFFENS. 

